In the beer brewing industry, it is known that beer must be carbonated to achieve the desired flavor and palate texture for the end consumer. One method of achieving carbonation in beers is known as krausening, which can be achieved by adding additional fermentable sugars to a beer while in a pressure vessel. This causes a secondary fermentation, a subsequent discharge of CO2, and a natural increase in carbonation to a known level. This method and the method of directly adding fermentable sugar to the beer is known as bottle or keg conditioning, and can leave an undesirable amount of residual yeast sediment at the bottom of the container that may be objectionable to some consumers. In addition, krausening can also takes a week or more to achieve a desired carbonation level.
Alternatively, many breweries and beer bottlers use a force-carbonation method to carbonate their beer, which is accomplished by applying pressurized carbon dioxide (CO2) to the container at a specified temperature. The volume of CO2 (the standard unit used to measure carbonation level in the industry) is easily controlled via a carbonation chart of temperature of the beer and pressure of the CO2. While this process will carbonated beer without additional yeast sediment, it also takes a week or more to dissolve the prescribed amount of CO2 in the beer. In order to expedite this process, a carbonation or carbonating stone can be used. The stone is typically a sintered stainless steel porous cylinder that can be placed into a serving vessel. Common stones contain pores having a diameter from about 0.5 to about 2 microns to deliver very small bubbles into the liquid.
These stones create small bubbles of CO2 to be exposed to the beer. The small bubbles present a very large surface area to the beer, speeding along the dissolution into the beer. However, the stones can be restrictive to CO2 flow and require high pressures from about 20 to about 30 pounds per square inch (PSI) to push CO2 through the stones at an acceptable rate. Additionally, the process still takes days to complete and is a relatively manual process of venting and charging, leading to a fairly uncontrolled level of carbonation due to the high CO2 pressures required wherein the beer may become over-carbonated or under-carbonated based on the skill of the operator.
Over-carbonation occurs when the equilibrium pressure at a given temperature is exceeded. In addition, the venting of the CO2 gas to allow a continual flow of CO2 is wasteful and expensive. Lastly, it is known to place a carbonation stone in-line with a hose running between the fermentation vessel to the dispensing vessel and injecting the CO2 as it is pumped from the fermentation vessel to the receiving vessel. Despite the speed of operation, it is not readily feasible to consistently control the level of carbonation in the beer, resulting in under or over carbonated beer that can drastically affect the beer quality.
It is a primary objective of this invention to provide a carbonation system and process that can overcome the variability in the carbonation level and reduce the time to carbonate from days or weeks to approximately an hour or less. It is also an objective of this invention to create a system and process that results in a consistently carbonated beer regardless of the operator's skill.